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flow conditions and the perennial nature of the creek. Based on the local topography, Grape Creek <br /> appears to be a gaining stream draining the Precambrian material immediately adjacent to it. <br /> The mine will be completed in the Precambrian material, which is saturated below the water table <br /> based on nearby borehole data, including monitoring wells associated with the mine.The mine is <br /> expected to intercept some ground water within that material and will be dewatered to allow for <br /> mining. The Precambrian material beneath the mine has limited primary porosity (pores and spaces <br /> intrinsic to the rock unit) and ground water encountered by the mine will be water stored in fractures <br /> (secondary porosity)that drain into the mine. Dewatering of ground water encountered by the mine <br /> will be required to facilitate mining. The dewatering of the mine will lower the water level within the <br /> mine and cause water from nearby, connected fractures to enter the mine. The dewatering of the mine <br /> will also result in ground water gradients towards the mine, causing water in the aquifer around the <br /> mine to flow into the mine and through the dewatering system. This dewatering will be required over <br /> the life of the mine, but could require relatively low dewatering rates depending on the level of <br /> interconnectedness between the fracture system around the mine. When dewatering ceases,the <br /> fractured rock aquifer system adjacent to the mine is expected to refill to a pre-mining condition. <br /> Any changes in water quality that occur within the mine or the affected area will be mostly captured or <br /> at least influenced by the mine dewatering that will cause any impact to the ground water system to be <br /> drawn towards and into the mine limiting the potential for changes in water quality to impact aquifers <br /> or wells at distance from the mine and the affected area. <br /> Accordingly,the mine does have the potential to impact ground water systems in the vicinity of the <br /> proposed mine as a result of the mine dewatering in the form of water level changes in the aquifers. <br /> The ground water level changes have the potential to indirectly impact surface water systems in the <br /> form of stream depletions. The areas adjacent to the mine in which ground water or surface water <br /> could potentially be depleted was determined using a MODFLOW model which was used to simulate <br /> dewatering of the mine,ground water level changes in the aquifer system, and depletions to surface <br /> streams. Details regarding the MODFLOW modelling are presented in Appendix L. Based on the <br /> modelling investigation ground water level impacts potentially resulting from dewatering were limited <br /> to no more than 5 feet at a distance of approximately 1.1 miles from the mine assuming interception of <br /> ground water and constant dewatering operations over the life of the mine.Wells and surface water <br /> features outside of this approximately 1.1-mile radius will essentially not be impacted by ground water <br /> level changes caused by the mine dewatering. <br /> Available Division of Water Resources well database information and mapping were used to identify <br /> wells located near the property and the results of a MODFLOW model of the mine dewatering were <br /> used to identify which of those wells were close enough that their potential for impact should be <br /> investigated further. This review identified 5 wells that should be investigated further. Information <br /> associated with these nearby wells are summarized in the table below. <br /> 36 <br />